Prior to a June, 1984 FCC decision, pay telephones were the exclusive province of local telephone companies. Others were precluded from the business of providing pay telephone services. Today, however, subject to state Public Utility Commission regulations, Customer Owned Coin Operated Telephone (COCOT) service is permitted. An outgrowth of COCOT service has been the private operation of institutional telephone services. As might be expected, this "privatization" of phone systems has created a number of technical challenges including the detection of a called party's response by dialing a pulse-dial telephone and, in the case of prison systems, the prevention of three-way calling.
Coin telephones owned by local telephone companies generally utilize DC signals to signal called-party-answer. This information is transmitted between telephone company central offices and then to the originating pay telephone telling it, in effect, to accept payment for the call. This information is not, however, normally communicated to conventional, i.e., regular business and residential, telephones nor has this information been available to COCOT equipment. Collect calls placed through COCOT equipment are typically handled by an Alternate Operator Service (AOS), thus providing the owner of the COCOT equipment with the ability to provide collect call service and bill users of that service for both intra- and inter-LATA calls. However, the use of an AOS for collect calls is expensive. In addition, it opens the possibility of fraudulent activity in certain instances.
In many institutions the phone calls placed by a patient/client or prison inmate are collect calls. Collect calls initiated by a patient/client must be indicated as such to the called party. In addition, calls placed by an inmate to an outside party often begin with a prerecorded message stating that the call or collect call is from "a prison" and is being placed by "prisoner's name." In the above cases the called party is usually asked to dial a digit, commonly a `0`, to accept the call or collect call and attendant charges. The phone system providing such service must be able to detect such acceptance both as a DTMF tone response from a touch-tone phone as well as detect the line current interruptions caused by the equivalent response on a pulse-dial telephone.
The clients/inmates in some institutions may be allowed to call only numbers on a preauthorized list in order to deter fraudulent activity. A prison phone system must be able to detect the called party flashing the hook switch in order to prevent the called party from activating three-way (conference) calling, dialing another number and then connecting the prisoner to an unauthorized phone number.
Accordingly, a need has arisen for a telecommunications system which can automate and simplify the processes currently handled by a traditional AOS. Specifically, a need has risen for a telephone station which can automatically route local and long distant calls without the intervention of an outside service or live operator, and which enables the telephone owner/service provider to charge for the completion of a call or collect call while preventing three-way calling.